NPR's Elizabeth Shogren reports the new requirements are a rare example of industry agreeing to tough environmental regulations.

ELIZABETH SHOGREN, BYLINE: The new standards were the result of many months of negotiation between the Obama administration, the state of California, the auto industry and environmental groups.

Transportation Secretary Ray LaHood says it was one of the best collaborations he's seen in 35 years in public office.

SECRETARY RAY LAHOOD: It couldn't have happened if we didn't get everybody around the table to listen to one another.

SHOGREN: The industry was interested in negotiating; it wanted prevent California and other states from setting their own standards.

Gloria Bergquist is the vice president of the Alliance of Automobile Manufacturers.

GLORIA BERGQUIST: For automakers, what we really think is critical is that we're going to have a single national program for fuel economy for the next 13 years.

SHOGREN: The new standards are the first ever designed to both improve fuel economy and slash greenhouse gas emissions. The way the government calculates it, the average new cars and light trucks in 2025 are expected to go an equivalent of 54.5 miles per gallon. Most drivers won't get this kind of mileage. The targets will vary based on the size of the vehicle. The rules give manufacturers incentives to produce electric vehicles and plug-in hybrids.

LISA JACKSON: Some of the cars on the road today seemed like science fiction just a few years ago. It's a great example of what American innovators are capable of when they are unleashed.

SHOGREN: But the new standards do have detractors. Republican presidential candidate Mitt Romney says they're an example of how over-regulation by the EPA is hurting the economy and consumers.

Amanda Henneberg is a spokeswoman for Romney.

AMANDA HENNEBERG: Governor Romney opposes, you know, these extreme standards that president Obama has imposed which will limit the choices available to American families.

SHOGREN: Environmentalists say the issue helps show voters what the consequences would be if they replaced President Obama with Romney.

Michael Brune is the executive director of the Sierra Club.

MICHAEL BRUNE: It offers one of the biggest contrasts between the president and Mitt Romney.

SHOGREN: The new standards target model years 2017 to 2025. Because that's such a long time frame, the government agreed to reevaluate how things are going after several years. It will examine a lot of things, such as whether the technology is turning out to be as affordable as predicted and if customers are actually buying the more efficient cars.